Creutzfeldt Jakob disease (CJD) is a fatal neurodegenerative disorder caused by prion agents. In 1996, another human prion disease, variant CJD, emerged in the United Kingdom. The purpose of this application is to continue an active, nationwide study begun in 1995 of recipients of blood products from blood donors subsequently diagnosed with classic CJD to assess the risk of blood borne transmission of this disease in the United States. The study will be conducted as follows: 1) maintain and increase collaborative relationships with US blood banks to identify blood donors diagnosed with CJD in the United States and gather available, relevant, medical and demographic information on such donors;2) trace CJD donor blood components to final disposition;3) maintain and enhance collaborative relations with final disposition sites and collect vital statistics information from pre-existing records about recipients of CJD blood components;4) maintain study information about the recipients of the blood components from CJD donors who were previously identified in this study and continue to monitor these recipients'vital status, including the causes of death should they die;5) continue a plan that will (a) search national, state, and local organizations databases to match vital statistics and causes of death for the component recipients, including utilizing non-National Death Index databases to confirm the vital status of the component recipients and (b) assess the risk of blood-borne transmission of CJD;6) publish and disseminate results of the study. Data that will be systematically collected from this study will help determine whether classic CJD is being transmitted by blood and blood components in the United States. PUBLIC HEALTH RELEVANCE: This study collects recipient outcome data to assess the potential risk of transmission of Creutzfeldt-Jakob disease (CJD) by blood components from donors who subsequently developed CJD. There are two phases to this study. A retrospective phase which includes identifying the CJD infected blood donors and the recipients of those blood units and a prospective phase that tracks the recipients of blood donated by CJD donors. During the retrospective phase we receive reports from blood centers, family members and the Centers for Disease Control and Prevention (CDC). Once we receive the report we notify the blood center (if previously not notified), the hospitals and/or transfusion centers identify the recipients and report the survival status and if deceased the date and cause of death of that recipient. If the recipient is listed as deceased we verify the date and cause of death with the National Death Index (NDI). If the recipient is listed as alive we move onto the prospective phase of the study. This consists of tracking the recipient to see if they are currently alive (as of the last available NDI data set) and if not the date and cause of death. We track the recipients by using the National Death Index plus database and other databases when needed. We match the recipient's information to the information in the database to determine if it is a match. The risk to the human subjects is minimal. For donors who are reported by the CDC and Blood Centers only the donor initials are available. For those individuals whose family members report the case, they receive an information letter and Consent for Participation and Release of Information. Investigation does not proceed unless the consent for participation is signed. Names of the family reported donors are kept in a secure cabinet with very limited personnel access. Only the donor initials are used when imputing the data in the database. The risk is minimal for the recipients. The surviving recipients are not notified of the tracking because to date there has not been a transfusion transmission of classic CJD. Notifying the recipient would cause undue stress and mental anguish. This would be an unnecessary harm to the recipient. All recipient information both death and alive are kept in a secure cabinet with very limited personnel access. Names, Date of Birth and Social Security Number of the recipients are reported in the database and the database can only be accessed by specific co-investigators.